When The World Is Ready For An Idea ...

When the world is ready for an idea, someone will provide it.  Or more usually, many people will provide it.  That is why there are patent lawyers and arguments about the first person to invent an airplane or invent the incandescent light bulb or the first person to invent just about anything.

Darwin gets all of the credit for the idea of evolution by natural selection, but each edition of his "Origin" included a larger list of people who had also proposed at least part of his idea.

The most important person that few people have heard of was Alfred Russel Wallace.  He not only came up with exactly the same idea, but by sending his outline to Darwin, he pushed Darwin into publishing his ideas sooner.  Darwin didn't want his ideas published until after his death, correctly predicting that many people who wouldn't read his book would nonetheless attack it. (Doesn't that sound like Fox News and the Murdoch publications?) 

What Darwin had that the others didn't were:

The leisure to devote his life to compiling mountains of data

The willingness to devote his life to compiling mountains of data

Important friends in the right places.

Here is an excellent animated story of Wallace, who was poor and unknown, courtesy of the New York Times..

The Animated Life of A. R. Wallace FLORA LICHTMAN AND SHARON SHATTUCK This paper-puppet animation celebrates the life of Alfred Russel Wallace, who is co-credited with Charles Darwin for the theory of natural selection.